Telephone-service observing system



Oct. 8, 1929. CHANTER 1,730,969

TELEPHONE SERVICE OBSERVING SYSTEM Filed March 25, 1927 3 Sheets-Sheet l Fl g /02 ZW/IL/I'J wan/er y $4 aw AjpfQmey Oct. 8 1929. I v A. J. CHANTER I 1,730,969

TELEPHONE SERVICE OBSERVING SYSTEM Filed March 25, 1927 3,5heets-Sheet 2 Oct. 8, 1929. CHANTER 1,739,969

TELEPHONE SERVICE OBSERVING SYSTEI Filed March 23, 1927 s Sheets-Shed 3 300 C 302 ll 303 I vL- y aoim m-g Patented Oct. 8, 1929 UNITED STATES PATENT OFFICE ARTHUR JOHN CHANTER, OF ALDWYCH, LONDON, ENGLAND, ASSIGNOR TO WESTERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, 11. Y., A CORPORATION OF NEW YORK TELEPHONE-SERVICE OBSERVING SYSTEM Application filed March 23, 1927, Serial No. 177,578, and in Great Britain March 31, 1926.

This invention relates to signaling systems and has for its object the provision of means for observing the operation of signaling equipment at a number of ofiices from a common or central point, and particularly of au tolnatic telephone equipment.

This invention is preferably embodied, specifically stated, in an observing position connected by two wire trunk lines with each ethos of the area. The apparatus at each office is so arranged that the trunk may serve a plurality of lines, but the initiation of a call on one line of those selected for observation when the trunk line is engaged with another line prevents the connection of the first mentioned line with the trunk during that call. If a line is extended over the observation trunk to the observing position when that position is engaged with a second trunk, the first. trunk is disconnected from the position and the line, and the line is prevented from reconnecting with the trunk until after the termination of the call. A visual indication of the number dialed is given to the observer by means of a pulsing circuit including one side of the trunk and a relay operated from the pulsing relay of the selector employed in extending the connection.

To carry out this invention, an oiiice conveniently located is selected and any desirable number of operators positions equipped with the necessary lamps, relays and record ing equipment for making observations. A plurality of two-wire trunk lines are provided which terminate at each position with means for connecting them to the common equipment and to prevent a plurality of such connections at one time. These trunk lines extend to the offices included in the exchange area, one or more as needed to each office. At these offices each trunk terminates in a plurality of jacks. A group of lines on which observation is desired may be connected with the trunk by means of plugs which are connected With the subscribers line by any convenient means, preferably a shoe at the main distributing frame and a three point connector at the intermediate distributing frame. Each trunk is provided with equipment whereby only one line may be observed at a time and the necessary signals are transmitted to the observing operator over the two Wires of the trunk.

The operation of the system will be more clearly apparent from a consideration of the following description in connection with the appended drawings in which Fig. 1 shows a plurality of subscribers lines and the multiple jacks and relays in which an observation trunk terminates;

Fig. 2 shows the equipment associated with the trunk at the local office; and

Fig. 3 shows the equipment located at the central observing position.

Subscribers lines 100 and 101 are two of a number on which observations are to be made. F or this purpose relay 102 is inserted in the line circuit of substation 100 by means of jack 103, plug 104 and shoe 105, which is inserted in place of one heat coil at the main distributing frame. Plug 106 has its tip, ring and sleeve connected to the corresponding conductors of the line circuit by any convenient means, not shown. With piug 106 inserted in jack 115, these conductors are extended to the observation trunk equipment. Similarly, relay 107 is inserted in the line circuit of substation 101 by means of jack 108, plug 109 and shoe 110 while plug 111 extends the tip, ring and sleeve conductors of the line circuit to the trunk over jack 121. Jacks 115, 121, etc., are connected in multiple, except for the operating circuits of relays 11", 120, etc,. which extend over individual armatures and contacts of relays 213 and 21 1.

When the subscriber at substation 100 now initiates a call by removing his receiver from the switchhook he completes a circuit for line relay 112 extending from battery through the right winding of relay 112, inner contact of relay 123, upper segment of shoe 105, tip of plug 104 and jack 103 through the winding of relay 102 in parallel with resistance 122, ring of jack 103 and plug 106i, lower segment of shoe 105, over the substation loop, through heat coil 113, outer contact of relay 123, and the left winding of relay 112 to ground. Relay 112 operates to cause the operation of the switch to extend the calling line to a first selector. The selector immediately connects ground to conductor 114, thereby completing a circuit over conductor 114, sleeve of plug 106 and jack 115, upper winding of relay 116, lower nor mal contact and winding of relay 117 to battery. Relay 116 operates, but relay 11? cannot operate through the resistance of relay 116. lhe operation of relay 116 on tends the tip, ring and sleeve conductors of the subscribers line circuit to the trunk equipment. In addition, it closes a circuit from ground at its next to uppermost contact, normal contact of relay 201 to the winding of relay 202 and battery. Relay 102 operated in series with relay 112 so that, when relay 116 operates a circuit is closed from ground at the uppermost contact of relay 116, front contact of relay 102, winding of relay 203 and battery. Relays 202 and 203 operate.

Relay 202 in operating closes a circuit from battery through the winding of relay 212, front contact of relay 202, lower front contact and winding of relay 116 to ground holding relay 116 operated. Relay 212 closes obvious circuits for relays 213 and 214. The operation of relay 213 closes a circuit from ground over the sleeve of jack 115, inner left front contact of relay 213 to the lower normal contact and winding of relay 117, in shunt of the winding of relay 116, operating relay 117. Relay 117 locks in a circuit from battery through its lower winding, lower alternate contact, and upper winding, to ground over the sleeve of jack 115'. Relay 117 is now dependent only on the sleeve of the calling subscribers line.

When relay 203 operates, it closes a circuit from ground. at the left back contact of relay 211, middle left front contact of relay 203, winding of relay 209 to battery. Relay 209 in turn closes an obvious circuit for relay 216. Relay 203 also closes a circuit from ground over the right back contact or relay 211, right front contact of relay 203, lower right winding of repeating coil 205, outer left contact of relay 206, right normal contact of relay 20?, lower contact of jack 208, over the ring conductor of the two wire trunk 200, lower contact of key 300, lower normal contact of key 301, lower back contact of relay 302, winding of relay 303, upper back contact of relay 302, upper normal contacts of keys 301 and 300, over the tip conductor of the trunk 200, upper contact of jack 208, left normal contact of relay 20?, alternate contact of relay 209, left back contact of relay 21.0, outer left front contact of relay 203 to battery through the winding of relay 215.

The equipment above the dotted line of Fig. 3 is located at the observing operators position but is individual to trunk 200. The equipment below the dotted line is common to all trunks terminating at the position. The equipment of the trunks is connected to the common apparatus in multiple, with the except-ion of the operating circuits of relays such as relay 302 which extend over individual armatures and contacts of relay 307. Relay 215 cannot operate in the above traced circuit, but relay 303 operates, lighting lamp 304 to inform the observing operator that a call has been initiated on a line having access to trunk 200. Relay 303 also closes a circuit from battery through the winding of relay 305, front contact of relay 306, which is operated as long as the position is occupied, both windings of relay 302, inner back contact of relay 30? to ground at the outer front contact of relay 303. Belay 302 closes a holding *ircuit for itself extending as previmrs traced through the upper winding of relay 2 and its outer upper front contact to ground the outer right back con tact of relay 308. Relay 302 also lights lamp 309 over its middle lower contact, the outer back contact of relay 308 to ground at the lower contact of relay 302, indicating that the trunk has been connected to the position equipment, and transfers the trunk conductors from the winding of relay 303 over the contacts of relay 308 to the operatofs headset and the wi .dings of relays 310 and 311. l Vith relay 302 operated, the tip conductor of the trunk, to which the relay 215 is connected, is extended to the winding of relay 310 and both relays operate. Relay e10 in operating closes a circuit for relay 312 an d lamp 313.

lv lOfi relay 212 operated, it closed an obvious circuit for relay 201. Therefore, when relay operates it closes a holding circuit for relay 202 over the alternate contact of relay 201. Relay 202 is slow-to-release thus preventing its release should relay 201 open the energizing circuit before relay 215 closes the holding circuit.

The connection of ground to sleeve conductor 114 also caused the operation of cutoff relay 1 3 which disconnects the line rclav 112 from the line circuit. However, battery and ground through the pulsing relay of the first selector are first connected to the tip and ring conductors holding relay 102 operated. The operation of relay 116 connects relay 217 across the tip and ring of incl-1 115, the circuit also extending over the right back contact of relay 207 and through resistance 213 which is shunted by the right ba k contact of relay 210. Relay 217 is shunted by the circuit through the substation and dial and does not operate. i Vhen the subscriber manipulates his dial this shunt is opened and relav 217 operates in series with the selector pulsing relay. *lowever, the resistance of relav 21; is so high that it does not prevent the re lease of the pulsing relay. The operation of relay 217 closes an obvious circuit for relay 210. Relay 210 in turn operates relay 206.

It also opens the shunt around resistance 218 assisting relay 217 to release,'in turn releasing relay 210, as soon as the dial springs reclose to shunt relay 217. Relay 206 being slow-to-release remains operated throughout each digit dialed.

Each time that relay 210 operates the circuit of relays 215 and 310 is opened and these relays release. At each release of relay 215 the holding circuit of relay 202 is opened but the slow character of this relay enables it to retain its armatures attracted throughout the digit. Each release of relay 310 closes a circuit from ground at its back contact, front contact of relay 312 to the call indicator. This indicator comprises a plurality of stepby-step switches, together with a master switch for directing the pulses to the proper register and may be of the character disclosed in the patent to A. E. Lundell and Tudor Van Amstel No. 1,456,508, issued May 29, 1923. The arcs of the switches are connected to lamps which are lighted to give a visual indication of the number dialed. The operation of relay 206 disconnects the sub scribers line from the amplifier, closes a substitute holding circuit for relay 212 and for relay 203 and opens the ring side of the trunk. When dialing is completed relays 217, 210 and 206 release.

he induced ringing tone or busy tone re turned to the subscriber also flows over plug 106, jack 115 and contacts of relay 206 to the input circuit of the amplifier. The condensers 219 and 220 are of large capacity so that the connection of the line to the observing trunk does not materially reduce the volume either of tone or of talking current over the connection. The use of the amplifier, however, increases the volume in the observing circuit so that the operator may listen comfortably.

Vhen the called subscriber answers, an impulse of metering current is applied to the sleeve conductor 114 to operate the calling subscribers meter (not shown). When relay 116 operated, conductor 114 was also extended through resistance 221 to the winding of relay 211. However relay 211 could not operate in series with resistance 221. Vhen metering potential is applied, relay 211 opcrates and closes a shunt at its inner left front contact around resistance 221, so that it remains operated following the cessation of the metering impulse. Relay 211 closes at its outer left front contact an obvious circuit for relay 207, which relay disconnects relay 217 from the subscribers line. In addition, relay 211 opens the circuit of relay 209 which in turn opens that of relay 216. During the interval between the operation of relay 207 and the release of relay 216, which period is measured by the slow releasing times of relays 209 and 216, the repeating coil is discon nected from the trunk and a circuit is closed from tone source 222, outer left front contact of relay 216, left alternate contact of relay 207, upper contact of jack 208, over the tip conductor of trunk 200, upper contacts of keys 300 and 301, inner upper front contact of relay 302, inner right back contact of relay 308 to ground over three paths, through relay 310 to ground, through the operators headset, to ground through relay 311 and over the inner left back contact of relay 308, inner lower front contact of relay 302, lower contacts of keys 301 and 300 over the ring conductor of trunk 200, lower contact of jack 208, right alternate contact of relay 207, inner left front contact of relay 216 to ground.

WVhen relay 216 releases to close its back contacts the repeating coil is reconnected to the trunk and relay 204 is operated in a circuit extending from battery, through the winding of relay 204, right front contact of relay 211, right front contact of relay 203, lower right winding of repeating coil 205, outer left back contact of relay 206, inner left back contact of relay 216, right alternate contact of relay 207, lower contact of jack 208, ring conductor of trunk 200, lower contacts of keys 300 and 301, inner lower front contact of relay 302, inner left back contact of relay 308, winding of relay 311 to ground. Relay 311 operates, lighting lamp 314. Relay 204 in operating supplies an additional holding ground for relay 202. While the tone was being sent, holding ground was supplied over the outer left front contact of relay 207 and the right contact of relay 216. Relay 215 is now again connected to the tip conductor of the trunk over the normal contact of relay 209 and the upper right winding of repeating coil 205 and thence to relay 310, both relays being held operated. The circuit is now in condition for the operator to listen to the conversation if she desires.

hen the calling subscriber restores his receiver to the switchhook, the circuit of relay 102 is opened and that relay releases, in turn releasing relay 203. Ground is removed from conductor 114, releasing relay 117 and relay 211. The release of relay 203 causes the release of relays 310 and 215 and opens the circuit of relay 204, but that relay is held over the left front contact of relay 202 and the right back contact of relay 203 to the winding of relay 311 and in turn holds relays 202, 116 and 212 operated. This release of relay 310 extinguishes lamp 313, indicating to the operator that the call has ended.

The trunk remains in this condition until released by the operation of key 315. This key closes an obvious circuit for relay 308. Relay 308 locks over its left front contact to ground at the outer lower front contact of relay 302. The operation of relay 308 opens the circuit of relays 311 and 204 and the locking circuit of relays 305 and 302, causing these relays to release. It also lights release lamp 316. With relay 302 released, relay 307 and, after an interval, relay 308 also re: lease and the operators equipment is restored to normal.

The release of relay 204 removes the last holding ground from the circuit of relay 202 and that relay releases, opening the circuit of relays 116 and 212. Relay 212 in releasing restores relays 213 and 21 1, and relay 116 in releasing disconnects the trunk apparatus from jack 115 and the subscribers line. The equipment is now ready to beoperated by the initiation of another call on the same or another line.

The operation of release key 315 at any time after the completion of a call will re lease the trunk and leave the line locked away from the trunk. The operation of relay 308 opens the circuit of relay 215 as well as of relay 20 1-, so that the holding circuits of re lay 202, and therefore of relays 116 and 212, are also opened. The release or relay 116 disconnects the trunk from the line, releasing relays'211, 207 and 203. With relay 11'? locked to the sleeve conductor, relay 116 cannot reoperate until after the call has terminated.

If a call should be originated on a second line of the group under observation, say line 101, while the trunk is engaged with line 100, the operated condition of relay 213 which exists throughout the observation, shunts the windin of relay 118 so that the ground connected to concludctor 119 imn'iediately operates relay 120 which locks to conductor 110 and opens the circuit of relay 118, preventing its operation when relay 213 is released by the operator. This insures that no line in a group under observation may be connected with the observing trunk after a call has been partially set up.

Incoming calls may also be observed. The connection of ground to the sleeve terminal of the called line by the connector switch operates relays 116, 117, 201, 202, 212 213 and 214 as above described. Since relay 102 is not operated at this time, relay 203 does not operate. Under these conditions relays 204 and 303 operate in series in a circuit which may be traced from battery through the winding of relay 2041, left front contact of relay 202, right back contact of relay 203, and thence over the trunk tlllOllQh the winding of relay 303 back to the repeating coil, normal contact of relay 209, left back contact 01 relay 210. to ground at the left back contact of relay 203. Relay 303 causes the extension of the trunk to the operatoids telephone as above described. Relay 20 ic held operated in series with relay 311, lighting lamp 314.

A circuit is now closed from. battery through the winding of relay 211 over the outer front contact of relay 201, right front contact of relay 201 to the sleeve conductor 11 1. Since resistance 221 is not included in this circuit relay 211 operates and closes the circuit for relay 207. l/Vhen ringing current is applied to the called line a. portion of it passes to the amplifier and through the repeating coil to the operator.

When the subscriber answers, relay 102 is operated in turn operating relay 203. lVith relay 203 operated, relay 204 is held operated and relay 215 is operated in series with relay o1. Relay 310 lights lamp 313. Release takes place in the manner above described.

is above noted, the apparatus at the operators position above the dotted line is individual to the trunk line while the remaining apparatus is common to all trunk lines ap peering the position. Should a call come under observation over trunk 200 while the common apparatus is engaged with another trunk, relay 303 will be operated but, since relay 307 in the common equipment is operted, relay 302 cannot be operated, its 0perating' circuit beingopen at a contact of relay 307. At the distant office relay 201 operates as above described, opening the energizing circuit of relay 202. Neither relay 215 nor 20 1 can operate under these conditions nor is relay 20"? operated. Therefore no alternative holding circuit is closed tor relay 202 and that relay releases after an interval. lVhen relay 202 releases the holding circuit of relays 116 and 212 is opened. and these relays release in turn releasing relays 213, 21 1, 201 and 203 leaving; relay 117 locked to the sleeve conductor until the call is terminated.

i i hat is claimed is:

1. In an automatic telephone system, an observing operators position, a plurality of trunks extending to said position, a plurality of lines for observation, a relay individual to each line associated with one of said trunks, and means effective when said trunk is engaged with one off said lines and a call is initiated on another line to lock the relay individual to said last mentioned line under the control of said line to prevent the connection of said second line with said trunk until after the termination of said call for said second line.

2. In an automatic telephone system, a plurality of oilices, a plurality of subscribers lines terminating in each ofiice, an observing operators position at one office, a trunk connccting said position with each oflice, means at each oilice for connecting any one of a number of subscribers lines with a trunk for observation, a called line number indicator at said position. and means associated with each trunk controlled directly from the subscribers line for operating said indicator over said trunk.

3. In an automatic telephone system, subscribers lines, an observing operators position, a called line number indicator at said position, a trunk extending to said position,

means for connecting any one of said subscribers lines with said trunk for observation, a relay associated with said trunk, a dial in each said line, means for energizing said relay when said dial opens said line, and means controlled by said relay to operate said indicator over said trunk.

4:- In an automatic telephone system, subscribers lines, an observing operators pos1- tion, trunks appearing at said position, means for connecting any one of said trunks with the equipment at said position, means for connecting any one of said subscribers lines with a trunk for observation, and means at said position to prevent the connection of more than one trunk with said position equipment at one time.

5. In an automatic telephone system, a plurality of otfices, subscribers lines terminating at each oilice, an observing operators position at one office, trunks appearing at said position, means for connecting any one of said trunks with the equipment at said position, means at each ofiice for connecting any one of said subscribers lines with a trunk for observation, means at said position to prevent the connection of said trunk with said position equipment if said equipment is engaged with a second trunk, and means thereupon automatically effective to disconnect said line from said trunk.

6. In an automatic telephone system, a plurality of ofiices, subscribers lines terminating at each office, an observing operators position at one office, trunks appearing at said position, means for connecting any one of said trunks with the equipment at said position, means at each oflice for connecting any one of said subscribers lines with a trunk for observation at the initiation of a call over said line, means at said position to prevent the connection of said trunk with said position equipment if said equipment is engaged with a second trunk, means thereupon automatically effective to disconnect said line from said trunk, and means to prevent the reconnection of said line with said trunk until after the termination of said call.

7. In an automatic telephone system, subscribers lines, an observing operators position, trunks appearing at said position, means for conecting any one of said trunks with the equipment at said position, means for connecting any one of said subscribers lines with a trunk for observation, at the initiation of a call over a line, and means for repeatedly observing on said line comprising means for preventing the disconnection of said line from said trunk and said position equipment following the termination of a, call.

8. In an automatic telephone system, a plurality of offices, subscribers lines terminating in each office, an observing operators position at one office, an operators telephone thereat, a trunk connecting said position with each office, means at each oflice for connecting any one of said subscribers lines with a trunk for observation, and a relay individual to each trunk at said operators position effective when operated to connect said operators telephone directly with the corresponding trunk.

9. In an automatic telephone system, a plurality of offices, subscribers lines terminating in each oflice, an observing operators position at one ofiice, an operators telephone thereat, a trunk connecting said position with each office, means at each ofiice for connecting any one of said subscriber lines with a trunk for observation, a relay individual to each trunk at said operators position effective when operated to connect said operators telephone directly with the corresponding trunk, and means responsive to the connection of a subscribers line with a trunk to complete an operating circuit for the relay individual to said trunk.

10. In an automatic telephone system, a plurality of ofiices, subscribers lines terminating in each otlice, an observing operators position at one office, an operators telephone thereat, a trunk connecting said position with each office, means at each oiiice for connecting any one of said subscribers lines with a trunk for observation, a relay individual to each trunk at said operators position effective when operated to connect said operators telephone directly with the corresponding trunk, an operating circuit and a holding circuit for 100 each relay, means responsive to the connection of a subscribers line with a trunk to complete the operating circuit of the relay individual to said trunk, said relay closing its holding circuit, and means to thereupon open 105 the operating circuit of the relays individual to all trunks.

11. In a service observing system, a subscribers line, means for extending a tele phonic connection from said line, an oper- 110 ators telephone, a trunk circuit for connecting said line with said telephone for observation, and means in said trunk circuit for permitting the operator to listen to sounds transmitted over said subscribers line without 115 int rfering with such sounds, comprising large capacity condensers and an amplifier.

In witness whereof, I hereunto subscribe my name this fourth day of March, A. D.,

ARTHUR JOHN CHANTER. 

